Math::Atan2

Math::Atan2(x, y): float: Calculates 2-argument arc tangent of x/y (same argument order as C atan2()); signs of both arguments determine the quadrant of the result.

Table 1. Parameters
x	number	Real number x (numerator)
y	number	Real number y (denominator)

Return

The angle in radians, in range −π..π

println(Math::Atan2(1, 0.5)); //Will print "1.107149"
println(Math::Atan2(0.5, 1)); //Will print "0.463648"